Pulling tool



Oct. '3, 1950 w,J FELTQN 2,524,698

PULLING ,TOOL

Filed Dec. 11, 1945 9' WJIZeZZam INVENTOR.

BY Z

Patented Oct. 3, 1950 PULLING TOOL Walter J. Felton, Mankato, Minn., assignor to Truth Tool Company, Mankato, Minn.

' Application December 11, 1945, Serial No. 634,225

1 Claim. 1

This invention relates to a tool designed for pulling gears, collars, or the like from shafts, studs, etc. I

It is an object of the invention to provide a simple and compact tool which can readily be applied to the work and, after being applied, can be actuated easily for the purpose of stripping the engaged parts from each other.

A further object is to provide a cam action for insuring quick application of the tool to the work and whereby the tool will be maintained in engagement with the work during the stripping operation.

Another object is to provide a tool utilizing a cam which is rotatable for the purpose of exerting a pull upon the engaged part without, at the same time, subjecting the pivots and other parts of the tool to excessive transverse strains.

With the foregoing and other objects in view, which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts hereinafter more fully described and pointed out in the claim, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed.

In the accompanying drawing the preferred form of th invention has been shown.

In said drawing Figure 1 is a front elevation showing the tool as applied to the work, a crosshead and cam embodied in the invention being shown partly in section.

Figure 2 is a top plan view thereof.

Referring to the figures by characters of reference, l designates a cross head having forked ends 2 through which are extended pivot bolts 3. Opposed arms 4 are mounted on these bolts within the respective forks and these arms converge at one end and terminate in stripping jaws 5 which are extended toward each other.

A thrust screw 6 threadedly engages the middle portion of the cross head I and is provided at one end with a pointed stud 1 while the other end has a head 8 adapted to be engaged by a wrench or the like. A cam 9 is mounted for free rotation on the bolt 6 and has oppositely disposed portions II] that have arcuate side walls offset or eccentrically positioned relative to the axis of the screw 6, thus to reduce progressively the diameter of the cam 9. This is best shown in Figure 2. These oppositely disposed portions in are also formed with inclined upper faces I l constituting cam surfaces.

Those portions of the arms 4 remote from the stripping jaws 5 are extended across diametrically opposed portions of the cam 9 and have inwardly extending pulling jaws I2 which overlie the respective cam surfaces 8 I.

Under normal conditions the cam 9 is positioned with the low portions thereof under the jaws l2 and as these low portions are located where the cam is of smallest diameter it will be obvious that with the cam thus positioned the arms 4 can be freely swung to move the jaws 5 apart, because the side walls and cam surfaces of cam 9 will be spaced away from adjacent portions of the arms 4 and jaws I2 respectively a distance sufficient to permit this swinging.

In practice, and with the cam positioned as described immediately above, the screw 6 is fed lengthwise within the cross head I until the jaws 5 can be placed under the part C to be pulled. The screw and the jaws 5 will now have been positioned roughly as in Figure 1, with the jaws 5 under part C and stud 1 applied to the end of the part S. Screw 6 is tightened until the stud and the jaws firmly engage the respective parts S and C after which the cam 9, which is rotatable freely on the screw 6, is rotated. The cam faces II are thus brought into tight engagement with the jaws [2 so that the cam serves as a wedge between jaws l2 and cross head I without, however, exerting any spreading action against the adjacent portions of the arms 4, since even at its point of greatest diameter, its side walls are still spaced from the adjacent surfaces of the arms 4. By subsequently rotating the screw 6 the cross head, with the cam 9 wedged between the crosshead and jaws I2, is fed along the screw, thereby causing the jaws 5 to pull on the art C while thrust is being exerted against the part S.

Importance is attached to the fact that cam 9 slides freely on the screw and, when rotated, does not exert a spreading action. It is merely a means for tightly filling the space between jaws l2 and the cross head, so that the pulling thrust extends from jaws 5 through arms 4, jaws l2, and cam 9, to the crosshead and screw. Consequently the pivot bolts 3 are not subjected to any transverse strain tending to bend or otherwise injure them. It is well known to those skilled in the art that pulling tools as heretofore constructed produce strain and wear on the pivot bolts and cause the parts to lock to such an extent that the thrust screw loses much of its effectiveness. Furthermore, in other types of pullers using cams or similar devices, said cams do not move freely but are in engagement with the threads of the feed screws and are held in place by them. The present invention is designed to overcome these difiiculties by providing a cam which, as before stated, is not held in position by the screw threads and does not exert a lateral thrust against the pivotal arms.

It will be noted that where the outermost portions of the cam terminate, there are provided radial shoulders l3 which permit gripping of the cam by the users hand for the purpose of rotating it to wedging position. These shoulders also provide surfaces against which a hammer or the like can be tapped for the purpose of tightening the cam when moved into wedging or chocking position.

What is claimed is:

A pulling tool including a, crosshead, a thrust screw threadable through the middle portion thereof, opposed arms pivoted between their ends.

to the ends of the crosshead, a stripping jaw and a pulling jaw at the respective ends of each arm, each of said jaws having an engaging surface in a plane substantially at right angles to its arm, and means wedgeable between the crosshead and pulling jaws and constituting a medium through which the force of said screw may be transmitted REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,259,036 Mitchell Mar. 12, 1918 1,376,340 Klay Apr. 26, 1921 1,471,259 Good Oct. 16, 1923 1,519,067 Smith Dec. 9, 1924 1,732,696 Ridenour Oct. 22, 1929 1,827,475 Keefer Oct. 13, 1931 

